Electrochemical wastewater treatment equipment: used for wastewater demulsification

Electrochemical oxidation wastewater treatment equipment | Chemical-free demulsification · Highly efficient removal of COD and emulsified oil, electrode modules do not scale or clog.

This equipment utilizes electrochemical oxidation technology, specifically designed for treating high-concentration, recalcitrant emulsion wastewater (such as cutting fluids, rolling fluids, and oily cleaning wastewater). It eliminates the need for demulsifiers, directly disrupting the electrical double layer at the emulsion interface through an electric field, causing oil droplets to coalesce and precipitate. Simultaneously, strong oxidizing substances (hydroxyl radicals (·OH), active chlorine, etc.) are generated at the anode, significantly degrading COD and removing color and toxicity. The system consists of a pre-filter, an electrochemical oxidation reactor, a dedicated high-frequency DC power supply, and a circulating water tank. It boasts advantages such as thorough demulsification, no sludge, no electrode clogging, no residual solid waste, high automation, and low operating costs, making it an ideal pretreatment or advanced treatment solution for oily wastewater from industries such as machining, petrochemicals, and metal surface treatment.

core components

Pre-filter: Basket filter or self-cleaning filter, removes large suspended solids and impurities, protecting the electrochemical electrodes.

Electrochemical electrode assembly: Employs corrosion-resistant, high-performance electrodes with internal flow guiding and water distribution structures.

High-frequency DC power supply: High-power pulse/DC power supply with stable voltage and current output, overload, short-circuit, and overheat protection; adjustable current/voltage density to adapt to different water qualities.

Circulating water tank: Made of PE or PP material, equipped with level control and a circulating pump for batch processing or continuous flow circulation.

Auxiliary piping and control cabinet: PLC fully automatic control, automatically handles liquid inlet, electrochemical treatment, circulation, and drainage; touchscreen operation; fault alarm.

Working principle

After large particles are removed by a pre-filter, the emulsion wastewater enters the circulating water tank and is then pumped to the electrochemical electrode by a circulating pump. Under the influence of an electric field:

Electrodemulsification: The current directly disrupts the double layer at the emulsion interface. The electric field interferes with the ordered adsorption layer of the emulsifier at the oil-water interface, reducing the mechanical strength and elasticity of the interfacial film. Droplets break down and merge, causing oil droplets to coalesce and float to the surface.

Electrooxidation: Strong oxidizing groups (·OH, O₃, active chlorine, etc.) are generated on the anode surface, breaking down the chains of large organic molecules, reducing COD and toxicity, and simultaneously removing color and odor.

Air flotation assistance: Microbubbles are generated at the electrode, adhering to oil droplets and flocs, accelerating their flotation and separation.

Treatment wastewater stratification: The upper layer of floating oil and scum can be scraped off or overflowed for removal. The lower clear liquid meets discharge standards or is reused. The system circulates until the set water quality is achieved.

Main advantages

No chemical additives required: Primarily relies on electric demulsification and oxidation, introducing no salt or secondary pollution.

Highly efficient demulsification and COD removal: For high-concentration emulsions (oil content thousands to tens of thousands mg/L), the demulsification rate is ≥95%, and the COD removal rate can reach 60-90% (depending on water quality).

Broad applicability: Not only suitable for emulsions based on mineral oil, synthetic oil, and vegetable oil, but also for treating recalcitrant wastewater containing phenols, dyes, surfactants, etc.

Easy operation: Fully automatic PLC control; adjusting the current/voltage adapts to different wastewater concentrations, eliminating the need for frequent adjustments to reagent ratios.

Long electrode life: The electrode modules are non-consumable, non-scaling, and non-clogging; corrosion-resistant and passivation-resistant, with a normal service life of over 2 years.

Can be used in conjunction with other processes: As a pretreatment, it can reduce the load on subsequent biological or membrane treatments; or as an advanced treatment to ensure compliance with emission standards.

Technical parameters

Processing capacity: 0.5 – 50 m³/

Rated power: 5 – 100 kW (depending on processing capacity and water quality)

Voltage: 0 – 20 V (adjustable)

Hydraulic retention time (HRT): Determined by water quality

COD removal rate: 60% – 90%

Demulsification rate (oil removal rate): ≥95%

Circulating water tank volume: 1 – 20 m³

Material: Reactor and tank are made of PP / PE / 304 stainless steel

Power supply: Customized as needed

Application areas

Wastewater from machining cutting fluids, grinding fluids, and wire drawing fluids; steel cold rolling emulsions and cleaning fluids; oilfield produced water and oily wastewater (demulsification and pretreatment); oily tank washing water and ship ballast water; removal of recalcitrant organic matter from chemical, pharmaceutical, and dyeing wastewater. We can provide electrode configuration and operating parameters based on wastewater pilot-scale test results or water quality parameters. Please send your water sample analysis report to obtain a customized solution.